Issue |
JNWPU
Volume 37, Number 3, June 2019
|
|
---|---|---|
Page(s) | 449 - 456 | |
DOI | https://doi.org/10.1051/jnwpu/20193730449 | |
Published online | 20 September 2019 |
Research on Skin-Friction Drag Reduction by Hydrogen Injection in Supersonic Boundary Layer
超声速边界层氢气喷注减阻研究
Science and Technology on Combustion, Internal Flow and Thermo-Structure Laboratory, Northwestern Polytechnical University, Xi’an, 710072, China
Received:
23
May
2018
In order to investigate the applicability of the skin-friction reduction technique using hydrogen injecting into turbulent boundary layer, three-dimensional numerical simulation was carried out for a constant-cross-confined-space with rearward facing steps. The flow characteristics near wall surface and development of wall shear stress were analyzed and compared under different coming flow and injection conditions. The simulation results show that the hydrogen injection can achieve around 13.5% skin-friction drag reduction under the coming flow Mach number of 2.3Ma or 2.8Ma. At 2.8Ma, the optimal reduction profit is 13.5% which is obtained when the equivalent ratio is 0.06. The gases mixings are gradually enhanced along the flow path. At the positions of shock wave-boundary-layer interactions, the mixings are first strengthened and then suppressed, and meanwhile, the wall shear stress and density changes with similar law that first decreases and then rebounds at the positions. The declines of skin-friction drag decrease along the flow direction, the best reduction area can profit nearly 60%.
摘要
针对带有后向台阶的等截面受限空间,通过三维数值模拟,开展了超声速内流道边界层氢气喷注减阻的研究,分析对比了2.3Ma,2.8Ma来流条件下等质量氢气喷注、2.8Ma来流条件下氢气以当量比0.03,0.06,0.1喷注后近壁区流动特征以及壁面摩擦阻力的发展。研究表明边界层氢气喷注在2.3Ma和2.8Ma来流条件下可以达到13.5%左右的减阻效果。2.8Ma来流条件下,当量比为0.06时减阻效果最优,降幅为13.5%。气体的扩散与掺混沿流向逐渐加强,激波与边界层相互作用处掺混会被先加强后抑制,壁面剪应力在该位置伴随密度先降低后反弹呈现相同的变化规律。摩阻降幅沿流向也逐渐减弱,最佳的减阻区域内可达到将近60%的减阻收益。
Key words: supersonic punching channel / near wall flow / hydrogen injection / skin-friction drag / skin-friction reduction / three-dimensional numerical simulation / turbulent boundary layer
关键字 : 超声速流道 / 近壁区流动 / 氢气喷注 / 摩擦阻力 / 减阻
© 2019 Journal of Northwestern Polytechnical University. All rights reserved.
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